<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>Hello World</h1>
    <button id="btn">点击</button>
    <button>点击2</button>
    <script>
        var btn = document.querySelector('#btn')
        var h1 = document.querySelector('h1')
        btn.addEventListener('click', function() {
            h1.innerHTML = 'Hello JS'
        });

        var btn2 = document.querySelector('button')
        btn2.addEventListener('click', function() {
            h1.innerHTML = 'Hello JS'
        });
        var obj = {
            data: {},
            log: function(data) {
                console.log(data)
            },
            change: function(data) {
            }
        }




    </script>
</body>
</html>